1. Field of the Invention
The present invention relates to a wireless communication device, a router, a wireless communication system, and a wireless communication method.
2. Description of the Related Art
In recent years, various wireless access schemes such as wireless LAN (Local Area Network) standardized by IEEE (Institute of Electrical and Electronics Engineers) 802.11a/b/g/n, UMTS (Universal Mobile Telecommunications System), and mobile communications systems like WiMAX are put to practical use and become widespread.
A wireless communication device with a wireless LAN interface can be connected to the Internet indoors through a wireless LAN access point connected to a broadband line (hereinafter referred to as a BB line) such as ADSL (Asymmetric Digital Subscriber Line), FTTH (Fiber To The Home) or CATV (Cable TeleVision).
Further, a wireless communication device with a mobile communication interface such as a mobile phone can be connected to the Internet through an indoor type small-sized base station ((hereinafter referred to as a femtocell base station) of a mobile phone such as UMTS or WiMAX connected to a BB line. Note that the femtocell is described in International Patent Publication No. 2006/54341, for example.
Although wireless communication schemes are highly developed in this manner, a transmission rate of a wireless communication path is generally about 1/10 that of a wired communication path. Therefore, when a wireless base station such as a femtocell base station or a wireless LAN access point is connected to the Internet through a BB line, the throughput between a wireless communication device and the Internet is limited by the throughput in the wireless communication path.
On the other hand, wireless communication devices having both a wireless LAN interface and a mobile communication interface are widespread, and such wireless communication devices can selectively use a plurality of wireless access schemes according to usage when they are located in an area where a plurality of wireless base stations such as a femtocell base station and a wireless LAN access point are available.
For example, in a mobile phone scheme standardized by 3GPP, handover between a UMTS and a wireless LAN is specified, and a wireless communication device (UMA/GAN) conforming to the mobile phone scheme can switch whether to use a mobile phone or a wireless LAN for data communication of one application according to radio conditions.